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Text File | 1995-01-25 | 18.8 KB | 974 lines

/* * arch/mips/kernel/entry.S * * Copyright (C) 1994, 1995 Waldorf Electronics * written by Ralf Baechle */ /* * entry.S contains the system-call and fault low-level handling routines. * This also contains the timer-interrupt handler, as well as all interrupts * and faults that can result in a task-switch. */ #include <linux/sys.h> #include <linux/autoconf.h> #include <asm/segment.h> #include <asm/mipsregs.h> #include <asm/mipsconfig.h> #include <asm/page.h> #include <asm/stackframe.h> #include <asm/regdef.h> #include <asm/processor.h> /* * These are offsets into the task-struct. */ state = 0 counter = 4 priority = 8 signal = 12 blocked = 16 flags = 20 errno = 24 #/* MIPS OK */ exec_domain = 60 #/* ??? */ ENOSYS = 38 .globl ret_from_sys_call .globl _sys_call_table .text .set noreorder .align 4 handle_bottom_half: /* * If your assembler breaks on the next line it's * time to update! */ lui s0,%hi(_intr_count) lw s1,%lo(_intr_count)(s0) mfc0 s3,CP0_STATUS # Enable IRQs addiu s2,s1,1 sw s2,%lo(_intr_count)(s0) ori t0,s3,0x1f xori t0,t0,0x1e jal _do_bottom_half mtc0 t0,CP0_STATUS # delay slot mtc0 s3,CP0_STATUS # Restore old IRQ state j 9f sw s1,%lo(_intr_count)(s0) # delay slot .set reorder reschedule: la ra,ret_from_sys_call j _schedule nop .align 5 .globl _handle_sys _handle_sys: .set noreorder .set noat SAVE_ALL .set at STI /* * Compute return address. For now we assume that syscalls never * appear in branch delay slots. For the Linux/MIPS standard * libraries this assumption is always try. */ lw t3,FR_EPC(sp) lw s1,FR_REG2(sp) li t0,-ENOSYS addiu t3,t3,4 sw t3,FR_EPC(sp) li t2,NR_syscalls bge s1,t2,ret_from_sys_call sw t0,FR_REG2(sp) # delay slot sll s1,s1,2 lw s1,_sys_call_table(s1) lw s0,_current beqz s1,ret_from_sys_call lw t0,flags(s0) sll t0,t0,2 # PF_TRACESYS bltz t0,1f sw zero,errno(s0) # delay slot lw a0,FR_REG4(sp) lw a1,FR_REG5(sp) lw a2,FR_REG6(sp) lw a3,FR_REG7(sp) lw t0,FR_REG3(sp) jalr s1 # do the real work sw t0,16(sp) # delay slot lw t0,errno(s0) sw v0,FR_REG2(sp) # save the return value subu t0,zero,t0 # t0 = -t0 beqz t0,ret_from_sys_call nop /* * Fixme: should set error flag */ j ret_from_sys_call sw t0,FR_REG2(sp) # delay slot .align 4 1: jal _syscall_trace nop # delay slot lw a0,FR_REG4(sp) lw a1,FR_REG5(sp) lw a2,FR_REG6(sp) lw a3,FR_REG7(sp) lw t0,FR_REG3(sp) jalr s1 # do the real work sw t0,16(sp) # delay slot lw t0,errno(s0) sw v0,FR_REG2(sp) # save the return value subu t0,zero,t0 beqz t0,1f nop # delay slot sw t1,FR_REG2(sp) /* * Fixme: should set error flag */ 1: jal _syscall_trace nop .align 4 ret_from_sys_call: lw t0,_intr_count # bottom half bnez t0,2f 9: lw t0,_bh_mask # delay slot lw t1,_bh_active # unused delay slot and t0,t1 bnez t0,handle_bottom_half lw t0,FR_STATUS(sp) # returning to supervisor ? andi t1,t0,0x10 beqz t1,2f mfc0 t0,CP0_STATUS # delay slot lw t1,_need_resched ori t0,0x1f # enable irqs xori t0,0x1e bnez t1,reschedule mtc0 t0,CP0_STATUS # delay slot lw s0,_current lw t0,_task lw t1,state(s0) # state beq s0,t0,2f # task[0] cannot have signals lw t0,counter(s0) # counter bnez t1,reschedule # state == 0 ? lw a0,blocked(s0) # save blocked in a0 for # signal handling beqz t0,reschedule # counter == 0 ? lw t0,signal(s0) nor t1,zero,a0 and t1,t0,t1 beqz t1,skip_signal_return nop jal _do_signal move a1,sp # delay slot skip_signal_return: .set noreorder .set noat 2: return: RESTORE_ALL .set at #ifdef CONFIG_DESKSTATION_TYNE /* * Deskstation Tyne interrupt handler */ .text .set noreorder .set noat .globl _deskstation_tyne_handle_int .align 5 _deskstation_tyne_handle_int: SAVE_ALL .set at CLI lui s0,%hi(PORT_BASE) li t1,0x0f sb t1,%lo(PORT_BASE+0x20)(s0) # poll command lb t1,%lo(PORT_BASE+0x20)(s0) # read result li s1,1 bgtz t1,Lpoll_second andi t1,t1,7 /* * Acknowledge first pic */ lb t2,%lo(PORT_BASE+0x21)(s0) lui s4,%hi(_cache_21) lb t0,%lo(_cache_21)(s4) sllv s1,s1,t1 or t0,t0,s1 sb t0,%lo(_cache_21)(s4) sb t0,%lo(PORT_BASE+0x21)(s0) lui s3,%hi(_intr_count) lw t0,%lo(_intr_count)(s3) li t2,0x20 sb t2,%lo(PORT_BASE+0x20)(s0) /* * Now call the real handler */ la t3,_IRQ_vectors sll t2,t1,2 addu t3,t3,t2 lw t3,(t3) addiu t0,t0,1 jalr t3 sw t0,%lo(_intr_count)(s3) # delay slot lw t0,%lo(_intr_count)(s3) /* * Unblock first pic */ lbu t1,%lo(PORT_BASE+0x21)(s0) lb t1,%lo(_cache_21)(s4) subu t0,t0,1 sw t0,%lo(_intr_count)(s3) nor s1,zero,s1 and t1,t1,s1 sb t1,%lo(_cache_21)(s4) jr v0 sb t1,%lo(PORT_BASE+0x21)(s0) # delay slot .align 5 Lpoll_second: li t1,0x0f sb t1,%lo(PORT_BASE+0xa0)(s0) # poll command lb t1,%lo(PORT_BASE+0xa0)(s0) # read result lui s4,%hi(_cache_A1) bgtz t1,Lspurious_interrupt andi t1,t1,7 /* * Acknowledge second pic */ lbu t2,%lo(PORT_BASE+0xa1)(s0) lb t3,%lo(_cache_A1)(s4) sllv s1,s1,t1 or t3,t3,s1 sb t3,%lo(_cache_A1)(s4) sb t3,%lo(PORT_BASE+0xa1)(s0) li t3,0x20 sb t3,%lo(PORT_BASE+0xa0)(s0) lui s3,%hi(_intr_count) lw t0,%lo(_intr_count)(s3) sb t3,%lo(PORT_BASE+0x20)(s0) /* * Now call the real handler */ la t0,_IRQ_vectors sll t2,t1,2 addu t0,t0,t2 lw t0,32(t0) addiu t0,t0,1 jalr t0 sw t0,%lo(_intr_count)(s3) # delay slot lw t0,%lo(_intr_count)(s3) /* * Unblock second pic */ lb t1,%lo(PORT_BASE+0xa1)(s0) lb t1,%lo(_cache_A1)(s4) subu t0,t0,1 lw t0,%lo(_intr_count)(s3) nor s1,zero,s1 and t1,t1,s1 sb t1,%lo(_cache_A1)(s4) jr v0 sb t1,%lo(PORT_BASE+0xa1)(s0) # delay slot .align 5 Lspurious_interrupt: /* * Nothing happened... (whistle) */ lui t1,%hi(_spurious_count) lw t0,%lo(_spurious_count)(t1) la v0,return addiu t0,t0,1 jr ra sw t0,%lo(_spurious_count)(t1) #endif /* CONFIG_DESKSTATION_TYNE */ #ifdef CONFIG_ACER_PICA_61 /* * Acer PICA interrupt handler dummy */ .set noreorder .set noat .globl _acer_pica_61_handle_int .align 5 _acer_pica_61_handle_int: la a0,acer_text jal _panic nop 1: b 1b nop acer_text: .asciz "Interrupt handler for Acer PICA not written yet" .align 2 #endif /* CONFIG_ACER_PICA_61 */ .text .set noreorder .set at .globl _interrupt .align 5 _interrupt: move s2,ra mfc0 t0,CP0_STATUS ori t0,t0,0x1f xori t0,t0,0x1e mtc0 t0,CP0_STATUS move a0,t1 jal _do_IRQ move a1,sp # delay slot mfc0 t0,CP0_STATUS ori t0,t0,1 xori t0,t0,1 la v0,ret_from_sys_call jr s2 mtc0 t0,CP0_STATUS # delay slot .globl _fast_interrupt .align 5 _fast_interrupt: move s2,ra move a0,t1 jal _do_fast_IRQ move a1,sp # delay slot la v0,return jr s2 nop # delay slot .globl _bad_interrupt _bad_interrupt: /* * Don't return & unblock the pic */ j return nop .globl _handle_tlbl .align 5 _handle_tlbl: .set noreorder .set noat /* * Check whether this is a refill or an invalid exception * * NOTE: Some MIPS manuals say that the R4x00 sets the * BadVAddr only when EXL == 0. This is wrong - BadVaddr * is being set for all Reload, Invalid and Modified * exceptions. */ mfc0 k0,CP0_BADVADDR mfc0 k1,CP0_ENTRYHI ori k0,k0,0x1fff xori k0,k0,0x1fff andi k1,k1,0xff or k0,k0,k1 mfc0 k1,CP0_ENTRYHI mtc0 k0,CP0_ENTRYHI nop # for R4[04]00 pipeline nop nop tlbp nop # for R4[04]00 pipeline nop mfc0 k0,CP0_INDEX srl k0,k0,31 beqz k0,invalid_tlbl mtc0 k1,CP0_ENTRYHI # delay slot /* * Not in tlb -> nested refill exception * Load the missing entry and return. This is the most * efficient way to regain the faulting address. */ dmfc0 k1,CP0_CONTEXT dsra k1,k1,1 lwu k0,(k1) # Never causes another exception lwu k1,4(k1) dsrl k0,k0,6 # Convert to EntryLo format dsrl k1,k1,6 # Convert to EntryLo format dmtc0 k0,CP0_ENTRYLO0 dmtc0 k1,CP0_ENTRYLO1 nop # for R4[04]00 pipeline tlbwr eret /* * Handle invalid exception * * There are two possible causes for an invalid (tlbl) * exception: * 1) pages that have the present bit set but the valid bit * unset. * 2) pages that don't exist * Case one needs fast handling, therefore don't save * registers yet. * * k0 now contains the bad virtual address. */ invalid_tlbl: /* * Remove entry so we don't need to care later */ mfc0 k0,CP0_INDEX lui k1,0x0008 or k0,k0,k1 dsll k0,k0,13 dmtc0 k0,CP0_ENTRYHI dmtc0 zero,CP0_ENTRYLO0 dmtc0 zero,CP0_ENTRYLO1 /* * Test whether present bit in entry is set */ dmfc0 k0,CP0_BADVADDR tlbwi # delayed, for R4[04]00 pipeline srl k0,k0,10 lui k1,%HI(TLBMAP) addu k0,k0,k1 ori k0,k0,3 xori k0,k0,3 lw k1,(k0) andi k1,k1,_PAGE_PRESENT beqz k1,nopage_tlbl /* * Present bit is set -> set valid and accessed bits */ lw k1,(k0) # delay slot ori k1,k1,_PAGE_ACCESSED sw k1,(k0) eret /* * Page doesn't exist. Lots of work which is less important * for speed needs to be done, so hand it all over to the * kernel memory management routines. */ nopage_tlbl: SAVE_ALL .set at STI /* * Create a Intel-style errorcode * Bit 0: P Present * 0 == Page not in memory * 1 == privilege violation * Bit 1: R/W Read/Write * 0 == ReadAccess * 1 == WriteAccess * Bit 2: U/S User/Supervisor * 0 == User mode * 1 == Kernel mode * * a0 (struct pt_regs *) regs * a1 (unsigned long) error_code */ lw a1,FR_STATUS(sp) move a0,sp srl a1,a1,4 andi a1,a1,1 jal _do_page_fault xori a1,a1,1 # delay slot j ret_from_sys_call nop # delay slot .text .globl _handle_tlbs .align 5 _handle_tlbs: .set noreorder .set noat /* * It is impossible that is a nested reload exception. * Therefore this must be a invalid exception. * Two possible cases: * 1) Page not used yet * 2) Page doesn't exist yet. Let the kernel handle the trouble. * * Test whether present bit in entry is set */ dmfc0 k0,CP0_BADVADDR srl k0,k0,10 lui k1,%HI(TLBMAP) addu k0,k0,k1 ori k0,k0,3 xori k0,k0,3 lw k1,(k0) andi k1,k1,(_PAGE_PRESENT|_PAGE_RW) beqz k1,nopage_tlbs /* * Present and writable bits set -> set accessed and dirty bits. */ lw k1,(k0) # delay slot ori k1,k1,(_PAGE_ACCESSED|_PAGE_DIRTY) sw k1,(k0) /* * Now reload the entry into the tlb */ ori k0,k0,0x1000 xori k0,k0,0x1000 lw k1,4(k0) lw k0,(k0) srl k0,k0,6 srl k1,k1,6 dmtc0 k0,CP0_ENTRYLO0 dmtc0 k1,CP0_ENTRYLO1 tlbwi eret /* * Page doesn't exist. Lots of work which is less important * for speed needs to be done, so hand it all over to the * kernel memory management routines. */ nopage_tlbs: nowrite_mod: /* * Remove entry so we don't need to care later */ mfc0 k0,CP0_INDEX lui k1,0x0008 or k0,k0,k1 dsll k0,k0,13 dmtc0 k0,CP0_ENTRYHI dmtc0 zero,CP0_ENTRYLO0 dmtc0 zero,CP0_ENTRYLO1 tlbwi SAVE_ALL .set at STI /* * Create a Intel-style errorcode * Bit 0: P Present * 0 == Page not in memory * 1 == privilege violation * Bit 1: R/W Read/Write * 0 == ReadAccess * 1 == WriteAccess * Bit 2: U/S User/Supervisor * 0 == User mode * 1 == Kernel mode * * a0 (struct pt_regs *) regs * a1 (unsigned long) error_code */ lw a1,FR_STATUS(sp) move a0,sp srl a1,a1,4 andi a1,a1,1 jal _do_page_fault xori a1,a1,3 # branch delay slot j ret_from_sys_call nop # branch delay slot .globl _handle_mod .align 5 _handle_mod: .set noreorder .set noat /* * Two possible cases: * 1) Page is rw but not dirty -> set dirty and return * 2) Page is not rw -> call C handler */ dmfc0 k0,CP0_BADVADDR srl k0,k0,10 lui k1,%HI(TLBMAP) addu k0,k0,k1 ori k0,k0,3 xori k0,k0,3 lw k1,(k0) andi k1,k1,_PAGE_RW beqz k1,nopage_tlbs /* * Present and writable bits set -> set accessed and dirty bits. */ lw k1,(k0) # delay slot ori k1,k1,(_PAGE_ACCESSED|_PAGE_DIRTY) sw k1,(k0) /* * Now reload the entry into the tlb */ ori k0,k0,0x1000 xori k0,k0,0x1000 lw k1,4(k0) lw k0,(k0) srl k0,k0,6 srl k1,k1,6 dmtc0 k0,CP0_ENTRYLO0 dmtc0 k1,CP0_ENTRYLO1 tlbwi eret .globl _handle_adel .align 5 _handle_adel: .set noreorder .set noat SAVE_ALL STI li t0,-1 sw t0,FR_ORIG_REG2(sp) jal _do_adel move a0,sp # delay slot j ret_from_sys_call nop # delay slot .globl _handle_ades .align 5 _handle_ades: .set noreorder .set noat SAVE_ALL STI li t0,-1 sw t0,FR_ORIG_REG2(sp) jal _do_ades move a0,sp # delay slot j ret_from_sys_call nop # delay slot .globl _handle_ibe .align 5 _handle_ibe: .set noreorder .set noat SAVE_ALL STI li t0,-1 sw t0,FR_ORIG_REG2(sp) jal _do_ibe move a0,sp # delay slot j ret_from_sys_call nop # delay slot .globl _handle_dbe .align 5 _handle_dbe: .set noreorder .set noat SAVE_ALL STI li t0,-1 sw t0,FR_ORIG_REG2(sp) jal _do_dbe move a0,sp # delay slot j ret_from_sys_call nop # delay slot .globl _handle_ov .align 5 _handle_ov: .set noreorder .set noat SAVE_ALL STI li t0,-1 sw t0,FR_ORIG_REG2(sp) jal _do_ov move a0,sp # delay slot j ret_from_sys_call nop # delay slot .globl _handle_fpe .align 5 _handle_fpe: .set noreorder .set noat SAVE_ALL STI li t0,-1 sw t0,FR_ORIG_REG2(sp) jal _do_fpe move a0,sp # delay slot j ret_from_sys_call nop # delay slot .globl _handle_bp .align 5 _handle_bp: .set noreorder .set noat SAVE_ALL STI li t0,-1 sw t0,FR_ORIG_REG2(sp) jal _do_bp move a0,sp # delay slot j ret_from_sys_call nop # delay slot .globl _handle_tr .align 5 _handle_tr: .set noreorder .set noat SAVE_ALL STI li t0,-1 sw t0,FR_ORIG_REG2(sp) jal _do_tr move a0,sp # delay slot j ret_from_sys_call nop # delay slot .globl _handle_ri .align 5 _handle_ri: .set noreorder .set noat SAVE_ALL STI li t0,-1 sw t0,FR_ORIG_REG2(sp) jal _do_ri move a0,sp # delay slot j ret_from_sys_call nop # delay slot .globl _handle_cpu .align 5 _handle_cpu: .set noreorder .set noat SAVE_ALL STI li t0,-1 sw t0,FR_ORIG_REG2(sp) jal _do_cpu move a0,sp # delay slot j ret_from_sys_call nop # delay slot .globl _handle_vcei .align 5 _handle_vcei: .set noreorder .set noat SAVE_ALL STI li t0,-1 sw t0,FR_ORIG_REG2(sp) jal _do_vcei move a0,sp # delay slot j ret_from_sys_call nop # delay slot .globl _handle_vced .align 5 _handle_vced: .set noreorder .set noat SAVE_ALL STI li t0,-1 sw t0,FR_ORIG_REG2(sp) jal _do_vced move a0,sp # delay slot j ret_from_sys_call nop # delay slot .globl _handle_watch .align 5 _handle_watch: .set noreorder .set noat SAVE_ALL STI li t0,-1 sw t0,FR_ORIG_REG2(sp) jal _do_watch move a0,sp # delay slot j ret_from_sys_call nop # delay slot .globl _handle_reserved .align 5 _handle_reserved: .set noreorder .set noat SAVE_ALL STI li t0,-1 sw t0,FR_ORIG_REG2(sp) jal _do_reserved move a0,sp # delay slot j ret_from_sys_call nop # delay slot /* * Exception handler table with 32 entries. * This might be extended to handle software exceptions */ .bss .globl _exception_handlers .align 2 _exception_handlers: .fill 32,4,0 /* * Table of syscalls */ .data _sys_call_table: .word _sys_setup /* 0 */ .word _sys_exit .word _sys_fork .word _sys_read .word _sys_write .word _sys_open /* 5 */ .word _sys_close .word _sys_waitpid .word _sys_creat .word _sys_link .word _sys_unlink /* 10 */ .word _sys_execve .word _sys_chdir .word _sys_time .word _sys_mknod .word _sys_chmod /* 15 */ .word _sys_chown .word _sys_break .word _sys_stat .word _sys_lseek .word _sys_getpid /* 20 */ .word _sys_mount .word _sys_umount .word _sys_setuid .word _sys_getuid .word _sys_stime /* 25 */ .word _sys_ptrace .word _sys_alarm .word _sys_fstat .word _sys_pause .word _sys_utime /* 30 */ .word _sys_stty .word _sys_gtty .word _sys_access .word _sys_nice .word _sys_ftime /* 35 */ .word _sys_sync .word _sys_kill .word _sys_rename .word _sys_mkdir .word _sys_rmdir /* 40 */ .word _sys_dup .word _sys_pipe .word _sys_times .word _sys_prof .word _sys_brk /* 45 */ .word _sys_setgid .word _sys_getgid .word _sys_signal .word _sys_geteuid .word _sys_getegid /* 50 */ .word _sys_acct .word _sys_phys .word _sys_lock .word _sys_ioctl .word _sys_fcntl /* 55 */ .word _sys_mpx .word _sys_setpgid .word _sys_ulimit .word _sys_olduname .word _sys_umask /* 60 */ .word _sys_chroot .word _sys_ustat .word _sys_dup2 .word _sys_getppid .word _sys_getpgrp /* 65 */ .word _sys_setsid .word _sys_sigaction .word _sys_sgetmask .word _sys_ssetmask .word _sys_setreuid /* 70 */ .word _sys_setregid .word _sys_sigsuspend .word _sys_sigpending .word _sys_sethostname .word _sys_setrlimit /* 75 */ .word _sys_getrlimit .word _sys_getrusage .word _sys_gettimeofday .word _sys_settimeofday .word _sys_getgroups /* 80 */ .word _sys_setgroups .word _sys_select .word _sys_symlink .word _sys_lstat .word _sys_readlink /* 85 */ .word _sys_uselib .word _sys_swapon .word _sys_reboot .word _sys_readdir .word _sys_mmap /* 90 */ .word _sys_munmap .word _sys_truncate .word _sys_ftruncate .word _sys_fchmod .word _sys_fchown /* 95 */ .word _sys_getpriority .word _sys_setpriority .word _sys_profil .word _sys_statfs .word _sys_fstatfs /* 100 */ .word _sys_ioperm .word _sys_socketcall .word _sys_syslog .word _sys_setitimer .word _sys_getitimer /* 105 */ .word _sys_newstat .word _sys_newlstat .word _sys_newfstat .word _sys_uname .word _sys_iopl /* 110 */ .word _sys_vhangup .word _sys_idle .word 0 #_sys_vm86 .word _sys_wait4 .word _sys_swapoff /* 115 */ .word _sys_sysinfo .word _sys_ipc .word _sys_fsync .word _sys_sigreturn .word _sys_clone /* 120 */ .word _sys_setdomainname .word _sys_newuname .word 0 #_sys_modify_ldt .word _sys_adjtimex .word _sys_mprotect /* 125 */ .word _sys_sigprocmask .word _sys_create_module .word _sys_init_module .word _sys_delete_module .word _sys_get_kernel_syms /* 130 */ .word _sys_quotactl .word _sys_getpgid .word _sys_fchdir .word _sys_bdflush .word _sys_sysfs /* 135 */ .word _sys_personality .word 0 /* for afs_syscall */ .word _sys_setfsuid .word _sys_setfsgid .word _sys_llseek /* 140 */ .space (NR_syscalls-140)*4 .bss .globl _IRQ_vectors _IRQ_vectors: .fill 16,4,0